Best Acids to Grow Cannabis

Created by
Added 13 May 2022

growing cannabis indoors

If you want your plant to grow to its fullest potential and reward you with big, resinous buds, you need to pamper it with the proper nutrients. But that doesn't stop at the Big 3 NPK macronutrients and other micronutrients. You must also focus on natural acids.

Your plant creates these acids on its own, naturally, but due to many reasons, it may not be producing enough of them. In such cases, or when you want the best results, you can give your plant an extra boost by administering these acids.

Doing so can lead to various benefits for your plant, like:

  • Your plant becomes more pathogen resistant
  • It can grow taller and bushier
  • The buds grow heavier with more terpene and cannabinoid content
  • The root turns into a giant ball that works efficiently 
  • Your plant becomes better adept at dealing with environmental stressors and much more

So, these acids are crucial, but should you administer them to your plant, and which acids are the best for optimal growth? In this article, learn what these acids are, how they benefit your plant, and how you can administer them. 

Humic and Fulvic Acids

humic acid

For decades, many farmers have been using humic and fulvic acids to grow healthier plants, and now, you can do so too.

Humic and fulvic acids are terrific growth enhancers for your plant. They make your roots healthier, allowing them to absorb nutrients more efficiently. As a result, your plant grows bigger and bushier. 

These acids are abundant in mineral-rich soil, but in hydroponic or soil-mix setups, they often lack quantity. Therefore, you should consider administering them to improve your plant's growing conditions and health.

And while these acids work great together, they have their unique benefits, too. Here's more on them.

Humic Acid

humic acid

Humic acid has to do more with soil health and growth. Humic acid occurs naturally once the dead organic matter in the substrate starts decomposing, thanks to microbes. 

However, it is a complex acid with high molecular weight than fulvic acid. Due to this, it has a chelating ability that makes it an excellent soil conditioner. In addition, it forms a molecular bond with various nutrients and minerals, making it easier for the roots to absorb them. 

It improves the availability and mobility of various essential nutrients like calcium, magnesium, iron, zinc, and magnesium. 

Fulvic Acid

fulvic acid

On the other hand, fulvic acid enhances your plant's ability to absorb nutrients. This acid has a lower molecular weight, more oxygen, and less carbon and is soluble in all pH levels. 

Hence, fulvic acid can cross through cell membranes and easily penetrate the leaves.

But when these acids work together, they lead to tremendous results, such as:

  • Better nutrient uptake thanks to the chelating ability
  • Healthy microbial activity in the substrate
  • Better water retention in the growing medium
  • Lower toxin uptake by the roots
  • Enhances photosynthesis process
  • Improved plant metabolism and growth

You can purchase a mix of these acids at your nearest gardening store. Just remember to talk to a professional there to know the right concentration for your plant and setup and follow the manufacturer's recommendations for administration.

You can apply these acids in various ways — you can mix them in the nutrient solution, use them as a foliar spray, or mix them directly into the grow medium. Choose what works best for you.

Abscisic Acid (ABA)


ABA is a natural hormone present in plants. It is essential for the plant's health as it helps the plant respond to various environmental stressors like drought, extreme temperatures, poor soil conditions, etc. Additionally, ABA is responsible for bud dormancy, stomatal control, and organ size control.

The plant produces this acid at the stem tips, in the terminal buds. Then, its growth slows down, and the leaves develop scales to protect themselves from the extreme temperatures of the winter. It also halts cell division. 

ABA is produced in the roots, too, in response to drought or poor soil conditions. In this case, it quickly moves to the leaves and closes the stomata cells, thereby reducing transpiration levels to retain moisture within the plant.

You can purchase abscisic acid at any gardening store — it is present in many off-the-shelf fertilizers. And you can administer it by spraying it directly on your plant or applying it to the substrate to improve your plant's tolerance to stress and improve its water management. 

Amino Acids

amino acid 3D structure

Amino acids are crucial for plant and animal health as they help the body synthesize protein. In addition, they serve as the building blocks of proteins. No wonder fitness freaks keep talking about amino acids. 

However, unlike us, your plant cannot source protein from milk or eggs. It must produce protein by first creating amino acids. Additionally, amino acids aid your plant in other ways, like:

  • Increases the production of chlorophyll for photosynthesis
  • Works as an easily absorbable alternative to nitrogen
  • Stimulates vitamin synthesis 
  • Improves plant's resistance to diseases and pests
  • Boosts cell wall strength

Your plant creates its own amino acids, but the process uses a lot of energy. Also, the plant may not be able to produce enough when stressed. Therefore, you can use amino acid fertilizers to compensate.

Amino acids are best absorbed via roots and leaves throughout the plant's vegetative and flowering phases. So, you can either choose a foliar application or mix it into the growing medium. 

When purchasing amino acid fertilizers, look for L-form amino acids. They come in two forms, D-form and L-form, and the latter is easier for the plant to absorb.

B9 Folic Acid

B9 Folic Acid

B9 folic acid, or vitamin B9, is present in plants naturally. It serves various essential functions. It also aids the plant in producing DNA and RNA — DNA contains the genetic code, and RNA transports the data to the cells, allowing the plant to synthesize proteins. 

It also helps with various metabolic functions related to carbohydrates, fats, and proteins, making the plant more robust and healthier. 

However, B9 folic acid is prone to rapid degradation under intense light. So, if you are growing an indoor plant, it is a good idea to give your plant an additional B9 folic acid boost. You can apply this acid by simply adding it to your regular nutrient solution or spraying it on the canopy.

Salicylic Acid

Salicylic acid

Salicylic acid is a natural plant hormone that helps your plant grow and aids other vital processes like transpiration, photosynthesis, and ion uptake. 

This acid is also responsible for enhancing flowering and seed germination. However, too much of this acid can be bad for flowering.

It also aids the plant in endogenous signaling, where a cell or tissue mediates the plant's defense against intrusions, thereby helping the plant fight off pathogens. Finally, it boosts the plant's systemic acquired resistance (SAR), reducing your reliance on pesticides.

You can purchase this acid at your local gardening store and administer it to your plant by spraying it, mixing in the substrate, or adding it to the compost. 

Whatever method you use, always follow the manufacturer's recommendations. However, as mentioned earlier, using too much of it can affect the flowering process of the plant. So, it is essential to use the recommended amounts only. 

Vitamin C

Also known as ascorbic acid, Vitamin C is another essential nutrient for your plant. According to a 2007 study by the University of Exeter and Shimane, specific enzymes in the plant naturally produce vitamin C. 

Scientists already know that vitamin C helps your plant tackle environmental stressors like ozone and UV radiation, which can break down the leaf molecules, and drought. But the study mentioned above stresses the importance of vitamin C. It notes that it's so essential that the plant cannot grow when it faces a lack of vitamin C. 

This acid helps your plant cope with other stressors, like the side effects of intense light, especially in indoor plants. And it helps the plant preserve nitrates, a combination of oxygen and nitrogen, which are vital for your plant's health.

Your plant can produce its own vitamin C, but you can give it that extra boost at times for the best results. Almost all gardening stores have various vitamin C products. Choose one best suited for your plant and growth condition and apply during the last weeks of growth. Remember to follow the manufacturer's usage recommendations. In addition, just because vitamin C is essential doesn't mean you drown the plant with it. Less is more, so make sure you add only a little for good results. 

Doing so would prepare your plant to fight stressors and lead to heavier buds. 

Summary: Best Acids to Grow Cannabis

If you want to grow healthy cannabis plants, you should consider using these acids as boosters. But whichever acid additive you use, ensure it is right for your plant and grow setup. And always use them in proper quantities, according to the manufacturer's recommendations. 

You can never go wrong with giving your plant a little boost, but never abuse products. No matter how good they seem, they will be detrimental to the plant if you use too much. Use just a little, and the result will be a healthy, bushy plant with resinous buds that would be a joy to smoke up. 


Sort by
Ascorbic acid is as effective as EDTA as a chelate . A whole book could be written on the role of chelates. What about lactic acid formed by the many varites of lactobacillicus? As used in many liquid ferment fertilizer s? Acids are for the most part a greatly misunderstood subject.